As the Department of Homeland Security continues to pour money into border security, evidence is emerging that illegal immigration flows have slowed to their lowest levels in at least two decades. The nation’s population of undocumented immigrants, which more than tripled, to 12.2 million, between 1990 and 2007, has dropped by about 1 million, according to demographers at the Pew Research Center.

A key — but largely overlooked — sign of these ebbing flows is the changing makeup of the undocumented population. Until recent years, illegal immigrants tended to be the young men who were streaming across the border in pursuit of work. But demographic data show that the profile of the typical immigrant now is much more likely someone who is 35 or older and has lived in the United States for a decade or more.

Homeland security officials in the Obama and George W. Bush administrations — who have more than doubled the U.S. Border Patrol’s size and spent billions on drones, sensors and other technology at the border — say enhanced security is driving the new trends.

“We have seen tremendous progress,” said R. Gil Kerlikowske, commissioner of U.S. Customs and Border Protection, which is part of the Department of Homeland Security. “The border is much more secure than in times past.”

The issue of border security is central to the broader debate over immigration reform that has roiled Washington in recent years and is emerging as a flash point in the 2016 presidential campaign. Congressional Republicans have insisted on greater border security measures before they would consider legalizing any immigrants who came to this country without proper documents.

President Barack Obama says the border has never been more secure and is urging a series of legislative steps to legalize millions of undocumented immigrants, streamline the visa system and further fortify the border. He has already moved to protect certain undocumented immigrants from deportation through executive actions. But these actions have faced resistance in the courts, including the decision Tuesday by a federal appeals court to keep one of the president’s signature immigration efforts from moving ahead.

What’s increasingly clear is that the shifting fortunes of the U.S. economy account for less of the ebb and flow of illegal immigration. Even as the U.S. economy bounces back from recession, illegal immigration flows have kept declining, especially from Mexico, according to researchers and government data. Since the 1990s, the opposite was true: the better the economy, the more people tried to come.

But, in reality, these facts will matter little to the barons of talk radio and those who make illegal immigration the centerpiece of their attempts to win votes, readers or audience share. (“Facts, schmacks. It came from the liberal media. It’s a LIE!!”) You can bet money in Vegas you’ll hear about how numbers are increasing (plan on buying a new time share with your winnings).

European Union authorities appealed to the bloc’s member states Wednesday to accept quotas of migrants to relieve the burden on southern states like Italy and Greece that are their main landing points.

The proposal by the European Commission, the executive arm of the European Union based in Brussels, is a response to concern that the bloc’s southern coastal states could become overwhelmed by the inflow of migrants making the dangerous crossing of the Mediterranean Sea in often unseaworthy vessels.

The International Organization for Migration said Wednesday that 1,840 migrants had been lost at sea or were known to have died while crossing the Mediterranean so far this year. That compares with 425 people during the same period last year.

The organization said Italy and Greece had received most of the 78,826 migrants who reached Europe this year. And while it was not able to make an exact comparison, it said arrivals in Italy compared with the same period last year were mostly unchanged at about 41,000. In Greece, however, there was a significant increase, with 37,000 people arriving so far this year compared with 34,000 during all of 2014.

The recent deaths of thousands of migrants trying to cross the Mediterranean prompted the bloc to draft the emergency response to stave off a worsening of the humanitarian crisis.

Angelino Alfano, the Italian interior minister, said Wednesday that he was cautiously optimistic that the European Union could approve a plan to help his country deal with the influx. A day earlier, the Italian prime minister, Matteo Renzi, said he believed that European Union leaders could reach an agreement at a meeting in late June.